[PATCH] build: fix grep invocation in cc-options

[PATCH] build: fix grep invocation in cc-options

[Ian Campbell]

# HG changeset patch
# User Ian Campbell <ian.campbell@citrix.com>
# Date 1317388735 -3600
# Node ID ddd1fcb1dff9f723d4f4c89f97ffef91b3e8a204
# Parent  222533abc1159bfa9c8cd522649c10079f6a6e9c
build: fix grep invocation in cc-options

Currently the build produces lots of
	Usage: grep [OPTION]... PATTERN [FILE]...
	Try `grep --help' for more information.

This is due to the "grep -- $(2)" in cc-options. It seems that the default of
reading stdin is disabled when using "--". I don't know if this is a bug in
grep or how it is supposed to be but we can work around it by explicitly
passing in "-"

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>

diff -r 222533abc115 -r ddd1fcb1dff9 Config.mk
--- a/Config.mk	Fri Sep 30 14:10:25 2011 +0100
+++ b/Config.mk	Fri Sep 30 14:18:55 2011 +0100
@@ -84,7 +84,7 @@ PYTHON_PREFIX_ARG ?= --install-layout=de
 #
 # Usage: cflags-y += $(call cc-option,$(CC),-march=winchip-c6,-march=i586)
 cc-option = $(shell if test -z "`echo 'void*p=1;' | \
-              $(1) $(2) -S -o /dev/null -xc - 2>&1 | grep -- $(2)`"; \
+              $(1) $(2) -S -o /dev/null -xc - 2>&1 | grep -- $(2) -`"; \
               then echo "$(2)"; else echo "$(3)"; fi ;)
 
 # cc-option-add: Add an option to compilation flags, but only if supported.